Cutter bit holder



Nov. 15, 1966 w. w. FEARON CUTTER BIT HOLDER Filed Nov. 20. 1963 MA 2+ nwww h mw lllil ///H\ .I Ill. III I o N INVENTOR; WILLIAM W. FEARON, BY

United States Patent Ohio Filed Nov. 20, 1963, Ser. No. 325,059 6 Claims. (Cl. 299-92) The instant invention relates to cutter bit holders, and more particularly, to cutter bit holders which may be utilized in mining apparatus for retaining the cutting bits.

The mining apparatus to which the cutter bit holder of this invention is applicable, is provided with a form of cutting and breaking means that is advanced into the mine face to remove material therefrom. The cutting and breaking means customarily comprises a plurality of cutter bits, which are the cutting elements of the mining apparatus. Each of the cutter bits is secured in a cutter bit holder, and may be removed therefrom for replacement of the cutter bits as they wear out. The replacement of the cutter bits of the mining apparatus is an ordinary maintenance procedure that is regularly performed to maintain the mining apparatus at optimum mining effectiveness. Accordingly, it is necessary that the cutter bits be quickly and easily removable from the holders therefor, and similarly, it must be possible to quickly and easily secure the cutter bits to the holders, in order that there be a minimum amount of down time for changing the cutter bits, during which the mining apparatus is out of operation and is non-productive. It is further required that the cutter bit be securely held in the cutter bit holder, inasmuch as the service is severe, and the forces acting on the cutter bit are such as to tend to work the cutter bit loose from the holder.

It is an object of the instant invention to provide an improved cutter bit holder which securely holds the cutter bit, and in which the cutter bit may be quickly and easily replaced.

It is a further object of the instant invention to provide an improved cutter bit holder in which the cutter bit is quickly and easily received simply by the application of force pressing the cutter bit into the holder.

It is another object of the instant invention to provide an improved cutter bit holder in which the cutter bit is quickly and easily removed by a simple prying action, forcing the cutter bit out of the holder.

It is also an object of the instant invention to provide an improved cutter bit holder in which the cutter bit is held in the holder by a yieldable plug that engages the cutter bit, said plug being deformable to permit the cutter bit to be received in and removed from the cutter bit holder.

Other objects of the instant invention will appear hereinafter, the novel features and combinations being set forth in the appended claims.

In the drawings:

FIG. 1 is an elevational view of the cutter bit holder of this invention, with a typical cutter bit;

FIG. 2 is a sectional view taken on the line 22 in FIG. 1; and

FIG. 3 is a partial sectional view taken on the line 3-3 in FIG. 2.

Referring to the drawings, the cutter bit holder has a body 11 that is formed with an upright socket 12 which extends through the body 11 from top to bottom. The socket 12 is illustrated as being rectangular in section to conform to the configuration of the cutter bit 15 which is received in the socket 12. However, it will be understood that other sectional shapes may be used for the socket 12 to conform to other shapes of cutter bits, the illustrations herein being merely exemplary. The cutter "ice bit holder 10 may be secured to or may be an integral part of a cutting arm, a cutting chain, an auger cutter or any of the other mine cutting devices that are well known in the art. The form of the cutter bit holder 10 as illustrated herein is merely exemplary, and it will be understood by those skilled in the art that the cutter bit holder 10'may have other forms, as dictated by the type of cutting device of which the cutter bit holder is a part, while still embodying the invention described herein.

The cutter bit 15 is formed with a depending shank 16 that is received in the socket 12. The shank 16 has a substantially rectangular sectional configuration so that the socket 12 and shank 16 fit together, and conform one to the other. Above the shank 16 the cutter bit is formed with a head 17, at the forward side of which there is secured the cutting tip 18 which leads the cutter bit 15 into the material of the mine face. The cutting tip 18' is formed of extremely hard, wear resisting material, such as is customarily utilized for cutting tools.

The cutter bit 15 includes a rear shoulder 19 which seats on the top of the holder body 11 to set the gauge of the cutter bit 15. The portion 20 of the cutter bit shank 16 adjacent to the shoulder 20 is in engagement with the holder body 11 in the socket 12. The front face 21 of the cutter bit shank 16 bears against the adjacent wall 22 of the socket 12. Thus, when the cutter bit 15 is advanced into the mine face, the cutting forces on the cutter bit 15 tend to rock the cutter bit 15 rearwardly. By such action there is established a force couple acting between the holder body 11 and the cutter bit 15 to resist the cutting forces on the cutter bit 15.

A transverse bore 24 extends intothe holder body 11 from one side wall 25 thereof. The bore 24 intersects the socket 12. However, the axis of the bore 24 is placed rearwardly of the rear wall 26 of the socket 12, so that a major portion of the bore 24 is behind the rear wall 26. The transverse bore 24 stops short of the other side wall 27 of the holder body 11, terminating in a conical bore portion 28. A bore 29, having a smaller diameter, extends from the conical bore portion 28 through to the other side wall 27 of the holder body 11.

A cylindrical plug 30, formed of yieldable material, is received in the bore 24. The plug 30 is preferably of substantially the same diameter as the bore 24, so as to be easily received therein. The plug 30 is disposed partially in the holder body 11 and partially in the holder socket 12. A major portion of the plug 30 is in the body 11, and a minor portion thereof extends into the socket 12, in effect forming a projection from the rear wall 26 thereof. The length of the cylindrical plug 30 is greater than the width of the socket 12, whereby the opposite ends of the plug 30 are seated in the holder body 11 beyond the opposite sides of the socket 12.

The holder body 11 has an uprightbore 31 extending downwardly from the top of the holder body 11 and intersecting the transverse bore 24 at a position spaced a short distance inwardly from the side wall 25. A roll pin 32 is press fitted into the bore 31 and extends downwardly into the transverse bore 24 to intersect the latter, thereby preventing the cylindrical plug 30 from working its way out of its position as above described, and out of the transverse bore 24. If it is desired to remove the cylindrical plug 30, then the roll pin 32 is forced upwardly into the bore 31, thereby opening the end of the transverse bore 24. A pin may then be inserted in the bore 29 against the end of the cylindrical plug 30 to force it out of the transverse bore 24.

The cylindrical plug 30 is formed of yieldable material whereby it may be deformed by the application of force thereto. At the one end of the plug 30, the conical bore portion 28 forms a recess, and at the other end of the plug 30 the open end of the transverse bore 24 forms a recess.

The opposite recesses so formed provide spaces into which the yieldable cylindrical plug 30 maybe deformed.

In FIG. 3 there is illustrated, in section, the cutter bit holder 10, with the cutter bit 15 secured thereto. The shank 16 is formed with a notch 35 at its rear side, into which the projecting portion of the plug 30 extends. The notch 35 includes an inclined surface 36 which is engaged by the plug 30 to retain the cutter bit 15 in the cutter bit holder 10. The inclined surface 36 moves over the cylindrical plug 30 when the cutter bit 15 is withdrawn from the cutter bit holder 10. The inclined surface 36 acts as a wedge pressing against the cylindrical plug 30 and applying force thereto, which deforms the cylindrical plug 30 into the recesses at the opposite ends thereof. In effect then, the cylindrical plug 30 is depressed out of the socket 12 and into the transverse bore 24 and the conical bore portion 28 to permit the cutter bit shank 16 to move past the plug 30, whereby the cutter bit 15 may be removed from the holder 10. The head 17 of the cutter bit 15 is formed with an undercut recess 37 which may be engaged by a suitable tool to apply a force for prying the cutter bit out of the cutter bit holder 10, with the action taking place as aforesaid.

The cutter bit shank 16 is formed with an inclined face 38 which extends downwardly from the notch 35. When the cutter bit 15 is inserted into the holder socket 12, the inclined face 38 meets the cylindrical plug 30. As force is applied to the cutter bit 15, to press it into the socket 12, the inclined face 38 wedges against the cylindrical plug 30, deforming it into the recesses 'at the opposite ends of the plug 30, whereby the shank 16 is received in the socket 12, and the projecting portion of the cylindrical plug 30 then snaps back into the socket 12 and engages with the notch 35 to hold the cutter bit 15 in the cutter bit holder 10.

The material for the cylindrical plug 30 must be selected to have the required properties for service as described herein. Thus, while the cylindrical plug 30 is required to be a yieldable member, it must also have such strength, durability and resilience as to avoid deterioration and damage of the plug in service. One material that has been found to be satisfactory is a polyurethane elastomer material having as its properties a tensile strength of 5000 pounds per square inch, a Shore A hardness of 92, a tear strength (ASTM Die C) of 675 pounds per square inch, and a compression modulus at ten percent deflection of 775 pounds per square inch. The material having these properties is deformable, but not easily so, and accordingly, the cylindrical plug 30 made of such material is an excellent retainer element for holding the cutter bit in the holder 10. The plug is extremely hard and has a substantial resistance to abrasion, thus avoiding damage to the plug 30 by the cutting forces which tend to severely vibrate the cutter bit 15.

Although a large force is required for deformation of the plug 30 formed of the exemplary material described above, nevertheless such forces are within the practical range for the service described therein. Thus, to remove the cutter bit 15, it could be pried out of the holder 10 by use of a crowbar engaged in the undercut recess 37. By such prying action, the cutter bit 15 may be quickly snapped out of the socket 12 of the cutter bit holder 10. Similarly, the cutter bit 15 can be easily forced into the socket 12 by striking it with a hammer, mallet or similar tool, and the cutter bit 15 is in effect, quickly snapped into the socket 12.

The cutter bit holder construction described hereinabove includes a positive bit holding device which will maintain the cutter bit 15 in the bit holder 10 during all severe conditions of service. The retaining element has a combination of properties of strength, hardness, durability, yieldability and resilience, which make it pe'rculiarly adaptable in the construction disclosed herein for holding the bit 15 in the bit holder 10. Along with this advantage, there is realized the further advantage of a construction in which the bit 15 may be quickly and easily removed from the bit holder 10 and a new bit 15 may be installed therein just as quickly and easily. In removing the cutter bit 15, it is merely snapped out of the cutter bit holder 10 by the application of a prying force thereto. In installing the cutter bit 15, it is snapped into the cutter bit holder 10 by the application of a force driving the shank of the cutter bit 15 into the socket of the cutter bit holder.

Obviously those skilled in the art may make various changes in the details and arrangement of parts without departing from the spirit and scope of the invention as defined by the claims hereto appended, and applicant therefore wishes not to be restricted to the precise construction herein disclosed.

Having thus described and shown an embodiment of the invention, what it is desired to secure by Letters Patent of the United States is:

1. A cutter bit holder for a cutter bit formed with a shank, said holder having a socket for the reception of the cutter bit shank, a yieldable solid plug of hard-wearing material for retaining the cutter bit in the holder, a complemental bore in the body of the holder which, is of substantially'the same cross-sectional size as said solid plug for the reception of the plug, said bore being intersected by the socket and a minor portion of the plug extending into the socket to engage the cutter bit shank with a major portion of said solid plug being disposed in said complemental bore, said holder being recessed at least beyond one end of said plug, the cutter bit being received in the holder by application of a force pressing the cutter bit shank into the socket and being removable from the holder by application of a force to withdraw the cutter bit shank from the socket, and the plug being yieldably deformed into the recess beyond the end of the plug to permit the cutter bit to be received in or removed from the bit holder.

2. A cutter bit and a holder therefor as recited in claim 1 in which the plug is formed of a polyurethane elastomer material.

3. A cutter bit holder for a cutter bit formed with a shank, said holder having a socket for the reception of the cutter bit shank, a yieldable cylindrical solid plug of hard-wearing material for retaining the cutter bit in the holder, a bore in the bodyof the holder which is of substantially the same diameter as said cylindrical plug and extending across the socket and beyond the opposite sides of the socket for the reception of the cylindrical plug with the opposite ends of the plug being disposed in the bore beyond the opposite sides of the socket, said bore being intersected by the socket and a minor portion of the plug extending into the socket on a chordal plane to engage the cutter bit shank and a major portion of said solid plug being disposed in said cylindrical bore, said holder being recessed beyond the opposite ends of the plug, the cutter bit being received in the holder by application of a force pressing the cutter bit shank into the socket and being removable from the holder by application of a force to withdraw the cutter bit shank from the socket, and the cylindrical plug being yieldably deformed into the recesses beyond the opposite ends of the plug to permit the cutter bit to be received in or removed from the bit holder.

4. A cutter bit and a holder therefor as recited in claim 3 in which the plug is formed of a polyurethane elastomer material.

5. A cutter bit holder for a cutter bit formed with a shank, said holder having a socket for the reception of the cutter bit shank, a yieldable cylindrical solid plug of hardwearing material for retaining the cutter bit in the holder, a cylindrical bore in the body of the holder which is of substantially the same diameter as said cylindrical solid plug and extending in from one side of the holder across the socket and beyond the socket to a position short of the opposite side of the holder for the reception of the cylindrical plug with the opposite ends of the plug being disposed in the bore beyond the opposite sides of the socket, said .bore being intersected by the socket and a minor portion of the plug extending into the socket on a chordal plane to engage the cutter bit shank and a major portion of said cylindrical solid plug being disposed in said cylindrical bore, said holder being recessed beyond the opposite ends of the plug (i) at the one side of the holder by the bore and (ii) at the opposite side of the holder by an extension of the bore, the cutter bit being received in the holder by application of a force pressing the cutter bit shank into the socket and being removable from the holder by application of a force to withdraw the cutter bit shank from the socket, and the cylindrical plug being yieldably deformed into the recesses beyond the opposite ends of the plug to permit the cutter bit to be received in or removed from the bit holder, means extending into the bore at the one side of the holder for securing the plug in the bore, said securing means being removable for withdrawing the plug from the bore, and an access bore extending References Cited by the Examiner UNITED STATES PATENTS 3,057,609 10/ 1962 Krekeler 299-92 3,063,691 11/1962 Osgood 29992 3,116,502 12/1963 Osgood 299-92 ERNEST R. PURSER, Primary Examiner. 

1. A CUTTER BIT HOLDER FOR A CUTTER BIT FORMED WITH A SHANK, SAID HOLDER HAVING A SOCKET FOR THE RECEPTION OF THE CUTTER BIT SHANK, A YIELDABLE SOLID PLUG OF HARD-WEARING MATERIAL FOR RETAINING THE CUTTER BIT IN THE HOLDER, A COMPLEMENTAL BORE IN THE BODY OF THE HOLDER WHICH, IS OF SUBSTANTIALLY THE SAME CROSS-SECTIONAL SIZE AS SAID SOLID PLUG FOR THE RECEPTION OF THE PLUG, SAID BORE BEING INTERSECTED BY THE SOCKET AND A MINOR PORTION OF THE PLUG EXTENDING INTO THE SOCKET TO ENGAGE THE CUTTER BIT SHANK WITH A MAJOR PORTION OF SAID SOLID PLUG BEING DISPOSED IN SAID COMPLEMENTAL BORE, SAID HOLDER BEING RECESSED AT LEAST BEYOND ONE END OF SAID PLUG, THE CUTTER BIT BEING RECEIVED IN THE HOLDER BY APPLICATION OF A FORCE PRESSING THE CUTTER BIT SHANK INTO THE SOCKET AND BEING REMOVABLE FROM THE HOLDER BY APPLICATION OF A FORCE TO WITHDRAW THE CUTTER BIT SHANK FROM THE SOCKET, AND THE PLUG BEING YIELDABLY DEFORMED INTO THE RECESS BEYOND THE END OF THE PLUG TO PERMIT THE CUTTER BIT TO BE RECEIVED IN OR REMOVED FROM THE BIT HOLDER. 